From the Research
Polar bear liver is toxic to humans due to extremely high concentrations of vitamin A, which can cause hypervitaminosis A poisoning if consumed, as evidenced by the most recent study in 2022 1. The high vitamin A content in polar bear liver is an evolutionary adaptation that helps these animals survive in the Arctic environment, where the vitamin aids in cold tolerance, immune function, and maintaining healthy skin and mucous membranes.
- Unlike humans, polar bears have developed metabolic pathways to safely process these high vitamin A levels.
- When excessive vitamin A is consumed, it cannot be properly metabolized and excreted by the body, leading to toxic accumulation, which can cause symptoms including nausea, vomiting, headache, dizziness, blurred vision, and even death in severe cases, as reported in a study on the acute and chronic toxic effects of vitamin A 2.
- The phenomenon of vitamin A toxicity from liver consumption is also seen in other Arctic animals like seals and huskies, though polar bears have particularly extreme concentrations.
- A study on hypervitaminosis A and bone found that excess vitamin A stimulates bone resorption and inhibits bone formation, which can lead to bone loss and contribute to osteoporosis development 3.
- It is essential to note that the assessment of vitamin A toxicity is critical, and monitoring vitamin A status with biomarkers sensitive to total liver reserves can help avoid negative consequences in individuals with hypervitaminosis A, as suggested by the 2022 study 1.